In LTE wireless communication systems, machine-type communications (MTC), including massive machine-type communications, refers to machine devices communicating with one another through wireless networks. Category-M devices (cat-M devices, sometimes referred to as LTE-M devices) typically refer to user equipment machines that are part of the Internet of Things (IoT) and communicate relatively small amounts of data with other machines via a wireless LTE network using the Transmission Control Protocol (TCP)/Internet Protocol (IP). Examples of Category-M devices include smart metering devices, sensors, healthcare devices, wearables and the like.
For MTC data transmission, the IP packet is broken into smaller radio resource blocks (RBs); the maximum number of RBs assigned to Cat-M devices is six, shared with other Cat-M devices at the time domain. If any one of the radio blocks is not received, the TCP packet cannot be reassembled, and retransmission of the radio block is required. Under poor radio signal conditions, because of radio block retransmissions and TCP server timeout, when two or more Cat-M devices concurrently download/upload data, the TCP session failure rate is high.